package com.mmall.concurrency.example.aqs;

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

/**
 * Created by Andrew on 2018/6/1.
 */
@Slf4j
public class SemaphoreExample1 {

    private final static int threadCount = 20;

    public static void main(String[] args) throws Exception{
        ExecutorService exec = Executors.newCachedThreadPool();

        final Semaphore semaphore = new Semaphore(3);


        for(int i=0; i<threadCount; i++){
            final int threadNum = i;
            exec.execute(()->{
                try{
                    semaphore.acquire(); // 获取一个许可
                    test(threadNum);
                    semaphore.release();  // 释放一个许可
                }catch(Exception e){
                    log.error("exception", e);
                }
            });
        }
        log.info("finish");
        exec.shutdown();
    }

    private static void test(int threadNum) throws Exception{
        log.info("{}", threadNum);
        Thread.sleep(1000);
    }
}
